Earnings Per Share - Computation of Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Numerator (both basic and diluted):
Net loss	$ (89,883)	$ (48,295)	$ (173,222)	$ (80,919)	$ (241,700)
Denominator:
Denominator for basic loss per share	42,602,128	40,167,876	41,869,855	40,360,194
Denominator for diluted loss per share	42,602,128	40,167,876	41,869,855	40,360,194
Basic loss per common share (dollars per share)	$ (2.11)	$ (1.20)	$ (4.14)	$ (2.00)
Diluted loss per common share (dollars per share)	$ (2.11)	$ (1.20)	$ (4.14)	$ (2.00)